Described herein are devices, systems, and methods for improving cardiac function, and for reducing ventricular volume. Many of the devices and systems described herein reduce ventricular volume by partition the ventricle into productive and non-productive portions (e.g., by partially occluding a small portion of the ventricle).
Annually, heart failure leads to millions of hospital visits internationally. Heart failure (including congestive heart failure) is the description given to a myriad of symptoms that can be the result of the heart's inability to meet the body's demand for blood flow. In certain pathological conditions, the ventricles of the heart become ineffective in pumping the blood, causing a back-up of pressure in the vascular system behind the ventricle.
The reduced effectiveness of the heart is usually due to an enlargement of the heart. A myocardial ischemia may, for example, cause a portion of a myocardium of the heart to lose its ability to contract. Prolonged ischaemia can lead to infarction of a portion of the myocardium (heart muscle) wherein the heart muscle dies and becomes scar tissue. Once this tissue dies, it no longer functions as a muscle and cannot contribute to the pumping action of the heart. When the heart tissue is no longer pumping effectively, that portion of the myocardium is said to be hypokinetic, meaning that it is less contractile than the uncompromised myocardial tissue. As this situation worsens, the local area of compromised myocardium may in fact bulge out as the heart contracts, further decreasing the heart's ability to move blood forward. When local wall motion moves in this way, it is said to be dyskinetic, or akinetic. The dyskinetic portion of the myocardium may stretch and eventually form an aneurysmic bulge. Certain diseases may cause a global dilated myopathy, i.e., a general enlargement of the heart when this situation continues for an extended period of time.
As the heart begins to fail, distilling pressures increase, which stretches the ventricular chamber prior to contraction and greatly increases the pressure in the heart. In response, the heart tissue reforms to accommodate the chronically increased filling pressures, further increasing the work that the now comprised myocardium must perform.
Drug therapy typically treats the symptoms of the disease and may slow the progression of the disease, but it cannot cure the disease. One of the only permanent treatments for heart disease is heart transplantation, but heart transplant procedures are very risky, extremely invasive and expensive and are performed on a small percentage of patients. Many patient's do not qualify for heart transplant for failure to meet any one of a number of qualifying criteria, and, furthermore, there are not enough hearts available for transplant to meet the needs of heart failure patients who do qualify.
Substantial effort has been made to find alternative treatments for heart failure. For example, surgical procedures have been developed to dissect and remove weakened portions of the ventricular wall in order to reduce heart volume. This procedure is highly invasive, risky and expensive and is commonly only done in conjunction with other procedures (such as heart valve replacement or coronary artery by-pass graft). Additionally, the surgical treatment is usually only offered to the most severe class of patients and, accordingly, is not an option for most patients facing ineffective drug treatment. Finally, if the procedure fails, emergency heart transplant is the only presently available option.
Ventricular partitioning devices offer a solution for treating heart failure. Described herein are ventricular volume reduction device that may also act as ventricular partitioning devices. These devices generally function to partition a patient's ventricle into a productive region and a non-productive region. For such devices to function properly, they are positioned in a specific location within the patient's heart chamber. Delivery of a partitioning device may be made complicated by the anatomy of a patient and by aspects or characteristics of the delivery device or partitioning device itself. Thus, it would be beneficial to provide devices, systems and methods for delivering and deploying a partitioning device in a patient's ventricle.
Described herein are ventricular volume reduction devices and methods that may be implanted to reduce the volume of the ventricle in a safe and controlled manner.